.px2rem(@name, @px) {
    @{name}: @px / 75 * 1rem;
}
.txh{
  display: flex;
}
html,doby{
  width: 100%;
  height: 100%;
    background: #f7f7f7;
}
#box{
  header{
    .px2rem(height,84);
    .px2rem(line-height,84);
    width: 100%;
    position: fixed;
    top: 0;
    left: 0;
    background: #fff;
    border-bottom: 1px solid #ccc;
    ul{
            .txh;
            justify-content:space-between;
      li{
              .px2rem(margin-left,30);
          .px2rem(margin-right,30);
          .px2rem(font-size,30);
      }
    }

  }
  section{
    
    .px2rem(margin-top,84);
    .px2rem(margin-bottom,84);
       ul{
         padding-top: 5%;
        li{
          text-align: center;
          .px2rem(font-size,26);
          margin-top: 5%;
        }
        li:nth-child(1){
          .px2rem(font-size,40);
        }
       }
  }
 
}